This could be really useful for doing a harmonic mix with a twist. Find a few tracks with matching keys that use a commonly sampled drum or bass line (example: the eight-beat drum beat from the beginning of "Blue Monday by New Order), which itself was ripped off from a Donna Summer B-side, then center the mix around that. There's a remix of a version of People Are Still Having Sex that uses it, I'd be interested to see what else has it hidden away.